The present invention relates to an apparatus for determining the orientation of the ophthalmic lenses belonging to a frame and to a method for determining the orientation of the ophthalmic lenses belonging to a frame likely to be implemented by virtue of said apparatus.
There are already known installations for measuring this orientation and more specifically for measuring the curvature of the frame.
The frames, commonly called spectacle frames, comprise two receiving half-parts forming two receptacles and into which the ophthalmic lenses are respectively driven. The two half-parts are linked together by a central bridge and they are respectively equipped with two arms opposite the central bridge. In this way, said two receiving half-parts extend symmetrically to one another relative to a main plane of symmetry dissecting said central bridge. Thus, the frames are designed to be adjusted on the face of a patient, the central bridge resting on his nose, the two half-parts respectively in front of his eyes and the two arms respectively on his ears. The curvature then represents the inclination of the two receiving half-parts, and consequently of the ophthalmic lenses, relative to a plane perpendicular to the abovementioned main plane of symmetry, or quite simply to the inclination of the two receiving half-parts, one relative to the other; an inclination of 180° would then correspond to a zero curvature.
The known apparatuses comprise a recording device, which includes a digital camera and means for processing the image supplied by the camera. They also comprise a first positioner element provided with a first reference mark and a second positioner element provided with a second reference mark. The first positioner element can be adjusted on the spectacle frame by defining a median plane of the frame, whereas the second positioner element is adjusted on the frame so as to define an orientation of the receiving half-parts.
Reference should be made to the document FR 2 903 504, which describes such an apparatus.
Thus, by virtue of the camera used to record an image of the positioner elements resting on the frame which is in turn on the face of the patient, the position of the first reference mark with respect to the second reference mark is then determined in order to deduce therefrom the curvature of the frame.
Although this type of apparatus is efficient, and does already make it possible to provide a good assessment of the curvature, it is necessary to provide even more accurate values of the inclination of the receiving half-parts. Above all, it is now necessary to offer simple equipment that does not require the people intended to use them to have any particular skills.
Thus, a problem that then arises and that the present invention aims to resolve, is to provide an apparatus that makes it possible to accurately obtain more accurate values of the curvature and also that is simple to use.
In order to resolve this problem, the present invention proposes an apparatus for determining the orientation of ophthalmic lenses belonging to a frame. This apparatus comprises, on the one hand, a recording device and, on the other hand, a reference-frame unit that can be installed on a frame while a patient is wearing it. Said frame has two receiving half-parts able to receive ophthalmic lenses and a central bridge that links said two half-parts; said two half-parts extending symmetrically to one another relative to said central bridge. Said reference-frame unit comprises two independent elements, a first element forming an arch having a central portion marked with a first reference mark and two fixing ends designed to be fitted respectively into the lateral edges of said half-parts to keep said central portion away from said frame, and a second element marked with a second reference mark, fitted onto said frame between the two lateral edges, said recording device comprising a camera pointing at the eyes of said patient from a determined viewing angle in order to record an image of said reference-frame unit fitted onto said frame. Said apparatus comprises processing means for assessing, from said image, the relative position of the two reference marks and for providing a value representative of the inclination of said half-parts relative to one another. According to the invention, the apparatus also comprises another camera separated vertically from said one camera and pointing at the eyes of said patient from another viewing angle; and the two cameras can be used to simultaneously record two images of said reference-frame unit fitted onto said frame from the two viewing angles in order to accurately assess the relative position of the two reference marks and to provide a value representative of the inclination of said half-parts.